Being able to optimize the performance characteristics of a vehicle is important for many reasons. An example performance characteristic is the amount of aerodynamic drag a vehicle experiences as it travels. Aerodynamic drag is defined as the resistance a vehicle experiences when passing through air. This resisting force is exerted on the vehicle parallel to the vehicle's trajectory or direction and opposite in direction to the vehicle's motion.
Additional performance characteristics including lift and mechanical resistance, such as wheel bearing resistance, also can affect the performance of a vehicle, such as a racecar. Lift is defined as the aerodynamic force which acts normal to the direction of the body in motion.
By minimizing the amount of drag a vehicle experiences as it moves through air, the fuel economy of the vehicle may be increased and the vehicle is able to travel at a higher speed for a given motive force (power). The minimization of drag is particularly important in the world of competitive automobile racing. A single pound of drag can result in about a 0.1 mile per hour (mph) difference in the average lap racing speed of a contemporary racecar. Ideally, a racecar should be setup to minimize drag and to maximize negative lift or downforce as it is often referred to.
Traditionally, testing to reduce drag, increase downforce, and/or evaluate additional performance characteristics, such as aerodynamic performance characteristics, has typically been accomplished in two ways, straight line testing and wind tunnel testing. As used herein, testing is defined as the gathering of data which may be used to evaluate a performance characteristic of a vehicle, such as aerodynamic drag or downforce. In conventional straight line testing the vehicle is moved relative to a support surface. In conventional wind tunnel testing air is moved over a stationary object, such as a vehicle, and forces on the object produced by the air movement are measured. In both cases the relative air speed must be high enough to produce measurable forces on the object.
In order to provide enough space, straight line testing is done in an open environment. One of the problems with testing in an open environment is that there is little chance of repeatability of environment conditions from a first test to a second test. One of the biggest and most important variables is the presence or absence of wind either in line with the movement of the vehicle or at an angle to the movement of the vehicle. Other variables include temperature and humidity. By not having a repeatable testing environment it is difficult to determine if changes in monitored performance characteristics, such as aerodynamic drag and down force, determined by data gathered during testing are due to changes in the design or setup of the vehicle, are due to changes in the environmental conditions, or are due to a combination of the two.
Wind tunnel testing provides the ability to control certain environmental parameters, but has several drawbacks. First, often a model of the vehicle must be made because the physical size of the wind tunnel cannot accommodate the full size vehicle. Second, the vehicle remains stationary during testing and air is forced past the vehicle. The performance characteristics of a stationary vehicle are not equivalent to the performance characteristics of a moving vehicle. The differences can be attributable at least to the fact that the car is not moving relative to the support or floor (especially important for race cars which have low clearances relative to the support), the air effects due to tire rotation are not present (especially important for open wheel vehicles), and the exhaust and other attributes of a running vehicle are not present though all of these elements can be modeled, but with increasing complexity and room for error.
As such, a need exists for a testing apparatus and method which provides a testing environmental which has the capability to provide generally repeatable environmental conditions, in particular wind conditions, and which permits a vehicle to be tested as the vehicle is functioning in its normal mode of operation.
In one exemplary embodiment, a method for testing a vehicle moving under its own power and having one or more sensors coupled thereto to evaluate at least one performance characteristic of the vehicle is provided. The method comprising the steps of providing a support having an upper surface, the support configured to support the vehicle and to permit the vehicle to travel across the upper surface; providing a generally repeatable static volume of air above the support; accelerating the vehicle under its own power along the support to a desired speed; detecting when the vehicle enters a test region of the support; detecting when the vehicle exits the test region of the support; monitoring one or more of the sensors coupled to the vehicle at least while the vehicle is in the test region of the support; and decelerating the vehicle to a stop. In one example, the step of providing the generally repeatable static volume of air above the support includes the step of providing an upper portion which cooperates with the support to define an enclosure which encloses a volume of air which is not generally influenced by air currents outside of the upper portion.
In another exemplary embodiment, an apparatus for testing a vehicle moving under its own power to evaluate at least one performance characteristic of the vehicle, the vehicle having a controller is provided. The apparatus comprising a support configured to support the vehicle and to permit the vehicle to travel over an upper surface of the support; an upper portion, the upper portion and the support cooperating to define an enclosure, the upper portion having an entrance, the entrance being positionable in an open position permitting the vehicle to ingress into and egress out of the enclosure and a closed position generally blocking the vehicle from ingress into and egress out of the enclosure; a first transmitter coupled to one of the support and the upper portion and located at a first position along a length of the support, the first transmitter configured provide an indication to the controller of the vehicle that the vehicle has passed the first position, the first position being chosen to provide a sufficient length of the support to permit the acceleration of the vehicle to a predetermined speed prior to reaching the first position; and a second transmitter coupled to one of the support and the upper portion and located at a second position along the length of the support spaced apart from the first position, the second transmitter configured provide an indication to the vehicle that the controller of the vehicle has passed the second position, the second position being chosen to provide a sufficient length of support subsequent to the second position to permit the vehicle to decelerate to a stop. In one example, the first transmitter and the second transmitter each emit a signal that is received by a receiver on the vehicle as the vehicle passes by the respective transmitter.
In a further exemplary embodiment, an apparatus for testing a vehicle moving under its own power to evaluate at least one performance characteristic of the vehicle is provided. The apparatus comprising a support configured to support the vehicle and to permit the vehicle to travel over an upper surface of the support; and an upper portion, the upper portion and the support cooperating to define an enclosure, the upper portion having an entrance, the entrance being positionable in an open position permitting the vehicle to ingress into and egress out of the enclosure and a closed position generally blocking the vehicle from ingress into and egress out of the enclosure; the upper portion further including a break away section removably coupled to the upper section and configured to become spaced apart from the remainder of the upper portion when the vehicle impacts the breakaway section, the breakaway section thereby permitting the vehicle to at least partially egress from the enclosure. In one example, the entrance includes a door and the breakaway section is a first portion of the door. In another example, the apparatus further comprises a second support positioned outside of the enclosure and adjacent the breakaway section, the second support configured to support the vehicle as it egresses from the enclosure through the breakaway section. In one variation the apparatus further comprises an impact member supported by the second support and configured to aid in the deceleration of the vehicle.
In still a further exemplary embodiment, an apparatus for testing a moving vehicle to evaluate at least one performance characteristic of the vehicle, the vehicle having a first component is provided. The apparatus comprising an enclosure having a first entrance and a support configured to permit the movement of the vehicle relative to an upper surface of the support, the first entrance configured to permit ingress and egress of the vehicle relative to the enclosure; a sensor adapted to be coupled to the vehicle and configured to monitor the first component of the vehicle and to provide sensor data corresponding to the first component of the vehicle; a first indicator located at a first position within the enclosure and a second indicator located at a second position within the enclosure, the second position being spaced apart from the first position and the portion of the support located generally between the first position and the second position defining a test region of the apparatus, the first indicator being configured to provide a first indication corresponding to the vehicle being at the first position and the second indicator being configured to provide a second indication corresponding to the vehicle being at the second location; and a controller operably coupled to the sensor and configured to collect information related to the sensor data at least when the vehicle is in the test region, the test region being of a length sufficient to permit the collection of information related to sensor data for a predetermined period of time. In one example, the predetermined period of time is at least about 5 seconds to about 7 seconds.
In yet a further exemplary embodiment, a method of testing a vehicle to evaluate at least one performance characteristic of a moving vehicle, the vehicle having an associated sensor. The method comprising the steps of providing an environment with generally repeatable environmental characteristics, the environment including an enclosure having a support surface; positioning the vehicle generally proximate to a first end of the support surface; accelerating the vehicle relative to the support surface to a first speed, the first speed being at least about 100 mph; capturing sensor date corresponding to the performance of the vehicle; and decelerating the vehicle to a rest position. In one example, the step of providing the environment comprises the steps of enclosing an existing tunnel to define an enclosed body of generally static air; paving a support surface on a bottom portion of the tunnel; and providing an entrance for ingress into and egress out of at least one end of the tunnel. In another example, the method further comprises the steps of monitoring an environmental condition selected from the group of temperature and humidity; and controlling a device to adjust the environmental condition.
In still yet a further embodiment, an apparatus for testing a vehicle moving under its own power to evaluate at least one performance characteristic of the vehicle is provided. The apparatus comprising a support configured to support the vehicle and to permit the vehicle to travel over an upper surface of the support, the support being of a sufficient length to permit the vehicle to accelerate, move at a desired speed and decelerate in its normal mode of operation; and an upper portion, the upper portion and the support cooperating to define an enclosure, the upper portion having an entrance configured to permit ingress into and egress from the enclosure; at least one turntable coupled to the support and configured to support the vehicle and to change the orientation of the vehicle, the at least one turntable being positioned at a first end of the support.
In an additional embodiment, an apparatus for testing a vehicle moving under its own power to evaluate at least one performance characteristic of the vehicle, the vehicle including at least one sensor is provided. The apparatus comprising an enclosure having a controllable environment; the enclosure including a first section for vehicle acceleration to a predetermined speed, a second section for gathering information from the sensor for evaluating at least one performance characteristic of the vehicle at the predetermined speed for a predetermined time, and a third section for vehicle deceleration to a stop; and a controller for controlling at least one environmental condition of the enclosure to provide for subsequent testing of the vehicle at generally repeatable environmental conditions. In one example, wherein the environmental condition is selected from the group of temperature and humidity. In another example, the apparatus further comprises a sensor within the enclosure to monitor the environmental condition and to provide an indication of the environmental condition to the controller. In yet a further example, the apparatus further comprises an alarm to monitor the environmental condition of the enclosure. In one variation, the alarm is a carbon monoxide alarm.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.